1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) and related methods for operations of displays, and more particularly, to an LCD having a plurality light sources of different colors sequentially emitting light within different duty cycles and related methods for operations of displays.
2. Description of the Prior Art
Since a liquid crystal display (LCD) has the advantage of low operating voltage and low power consumption, it has a great potential to replace the conventional, cumbersome cathode ray tube terminal (CRT).
Refer to FIGS. 1 and 2. FIG. 1 is a schematic diagram of an LCD panel 2 of the prior art, and FIG. 2 is a schematic diagram of a back light source 3 and a pixel 20 of the LCD panel 2. The conventional liquid crystal display comprises an LCD panel 2, and a back light source 3. The LCD panel 2 has a plurality of pixels 20, each constituted by red, green, and blue sub-pixels, each sub-pixel embedded with red, green, or blue color filters 21, 22, or 23, respectively. The back light source 3 emits white light in general. The white light emitted from the back light source 3 is filtered by the color filters 21-23 for being converted into light of red, blue, and green colors.
The liquid crystal in every sub-pixel is controlled by scan signals and data signals. Red light, green light, and blue light are generated in different brightness at the same time through a corresponding color filter 21-23 in the corresponding sub-pixels. The red light, the green light, and the blue light are mixed to form colors that a human can recognize. To prevent optical interfere between the emitting light through different color filters 21-23 from the back light source 3, a black matrix (BM) should be disposed between the different color filters 21-23.
However, the arrangement of black matrixes will reduce the aperture ratio, the utility rate of the light source, and light efficiency, and increase the energy consumption. Therefore, emitting light of different colors in different time frames has been taught. Refer to FIG. 3. As shown in FIG. 3, a time frame is divided into three durations, in which red light, green light, and blue light are emitted, respectively. Through persistence of vision, the red light, green light, and blue light will form a desired color, rather than three separate colors.
Human can be affected by full-color images without any color filters according to the method of emitting light of different colors in different time frames, a.k.a., the method of color sequence. Compared to liquid crystal display with color filters, a display without any color filters increases resolution and aperture ratio three fold, saves manufacturing cost of a color filter, and offers reduced power consumption.
However, as shown in FIG. 3, which is a timing chart showing light sources of different colors emitting with the same duty cycles within different durations according to the prior art, every duration (duty cycle) for emitting different colors is the same. When the white light, formed by red light, green light, and blue light in this method, is not within a tolerance of a standard point on a Commission Internationale del'Eclairage (CIE) chart, it is not easy to adjust the mixed white light to become standard.